Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 60-year-old asymptomatic man is evaluated during a routine examination. He has a long history of heart murmur. With normal daily activities, he has not experienced shortness of breath, chest discomfort, or palpitations.

Blood pressure is 138/78 mm Hg, pulse rate is 82/min and regular, and respiration rate is 16/min. BMI is 27. Cardiac examination shows normal jugular venous pressure with hepatojugular reflux. There is a regular rhythm and a grade 3/6 holosystolic murmur at the apex that radiates to the axilla. An S₄ is heard. Lungs are clear to auscultation bilaterally.

Electrocardiogram shows sinus rhythm with late R/S transition in the precordial leads. Transthoracic echocardiogram shows mild left ventricular hypertrophy with an ejection fraction of 65%. The left ventricular end-diastolic diameter is 52 mm and end-systolic diameter is 38 mm. There is bileaflet mitral valve prolapse without calcification but severe mitral regurgitation is present. The left atrium is moderately dilated. There is mild tricuspid valve regurgitation with an estimated right ventricular systolic pressure of 60 mm Hg.

Which of the following is the most appropriate treatment for this patient?

A: Begin bosentan
B: Begin lisinopril
C: Mitral valve repair surgery
D: Mitral valve replacement surgery

MKSAP Answer and Critique

The correct answer is C: Mitral valve repair surgery.

This patient should undergo mitral valve repair surgery. He has severe asymptomatic mitral regurgitation with normal left ventricular systolic function but evidence of pulmonary hypertension. Indications for surgical intervention for mitral regurgitation include (1) left ventricular ejection fraction below 60%; (2) left ventricular end-systolic diameter greater than 40 mm; (3) severe pulmonary hypertension at rest (pulmonary artery systolic pressure >50 mm Hg) or during exercise (>60 mm Hg); or (4) new onset of atrial fibrillation. In this patient, the right ventricular systolic pressure (and therefore, the pulmonary artery systolic pressure) at rest is significantly elevated.

Although this patient has pulmonary hypertension, the presence of left-sided heart disease with elevated left atrial pressure is the likely cause, rather than idiopathic pulmonary arterial hypertension. Treatment with a pulmonary vasodilator, such as bosentan, may worsen heart failure symptoms by increasing pulmonary blood flow with fixed, elevated pulmonary venous pressure.

Lisinopril or other ACE inhibitors theoretically reduce left ventricular afterload and regurgitant volume. Acute use of afterload-reducing medications, particularly intravenously, may be beneficial in patients with severe mitral regurgitation and decompensated heart failure, if the blood pressure is acceptable. However, chronic oral treatment with ACE inhibitors or other vasodilators has not been shown to reduce progression of mitral regurgitation or cardiac events.

Mitral valve repair—rather than replacement—has important benefits, including higher left ventricular ejection fraction after surgery and better long-term survival. In addition, repair does not require long-term anticoagulation and its associated risks compared with mechanical valve replacement (commonly performed for the mitral location for its longer durability compared with a biologic valve). The likelihood of successful repair is dependent on the mitral valve anatomy as well as surgical operator and center experience.

Key Point

• In asymptomatic patients with severe mitral regurgitation, pulmonary hypertension at rest or during exercise is an accepted indication for mitral valve surgery.

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